1. Field of the Invention
The invention relates, in general, to a method for sterilizing medical instruments with steam and, in particular, to a sterilization container useful for flash sterilization which includes a filter that permits maximum steam penetration and prevents microorganisms and dust from entering.
2. Description of Related Art
Steam sterilization is a common method used for the sterilization of items, especially medical instruments by processing the items in an autoclave and exposing them to high pressure steam. This method requires the wrapping of individual items, heating the items with steam and then waiting for a drying/cooling period. Often during surgical procedures commonly used instruments need to be quickly sterilized after use or inadvertent contamination. Under such circumstances the standard autoclave method would take too long. An alternative sterilization method, which can be used under these circumstances, is known as flash sterilization. In flash sterilization metal instruments are not wrapped and are heated directly by the steam allowing sterilization in a reduced period of time. One drawback to the use of flash sterilization is the lack of a drying period. When the items are still moist and hot from sterilization, microorganisms and dust can contaminate the items when they are transported from the autoclave/sterilizer.
One common design for containers for flash sterilization is described in U.S. Pat. Nos. 5,097,865 and 4,748,003. Such containers use valves which require greater than atmospheric pressures to open the valves and allow the high pressure steam to enter the container but are closed under normal pressure conditions. This approach has a number of disadvantages. Such containers must be opened to allow the steam to escape, thus breaking the sterile field. Even if kept sealed, these containers cannot maintain the sterile field for longer than 24 hours. Also, the high temperature, high pressure valves needed for this method are very complex and very expensive.
The present invention facilitates the use of flash sterilization while retaining the advantage of standard autoclave sterilization by maintaining the sterility of the items in the sterilization container. Instead of a costly, complicated valve system the present invention uses a passive filter system which is capable of allowing steam to enter and exit the container and still keeping microorganisms and dust out, maintaining the sterile field in the container for long term storage.